Photographic cameras of the instant processing variety generally are categorized in providing for a relatively larger film format. This larger film size stems basically from a requirement that a resultant developed picture must be large enough for utilization without resort to enlargement techniques. Many models of these cameras and related film, as currently marketed, in addition to utilizing the larger format size, also provide a film geometry selected to achieve a more enhanced or artistically desirable image framing. For example, the film recorded image has an elongate rectangular shape.
When utilized in an appropriate camera, the instant processing film or photosensitive material is packaged in given quantity within a molded plastic cassette structure, one flat surface of which is formed to define an opening, the periphery of which is of rectangular shape corresponding with the noted image format. To reinforce this periphery or edge, a small ridge of rectangular cross-section is integrally molded therealong. This ridge is considered to serve the additional function of assuring proper alignment and fitting of the cassette and opening at the exposure plane of the camera. Generally, when the film laden cassette is loaded within a camera, the ridge may slightly deform to fit within a corresponding cavity formed with the rear of the camera body. This cavity is formed under very close tolerance considerations during camera fabrication to assure proper positioning of a film unit at the image plane.
Following cassette insertion, the camera is readied for use by manually pulling a tab which effects the removal of an opaque, web-like dark slide to permit exposure of a forwardmost photosensitive film unit within the cassette.
Considering now in more detail the noted larger film format size and geometry, it may be noted that the consuming public long has held an interest in smaller format, "wallet-size" photographs. Such size is easily carried and accessible, but of a size perhaps smaller than that desired for mounting within photographic albums. It would be desirable to provide a capability for generating such smaller format image size utilizing inexpensive cameras of the instant processing variety, but without wasting valuable film and without requiring elaborate modification of those cameras already sold and in use by the general public. Such conversion must be so simple as to be capable of being carried out by the typical amateur user of the camera.
Looking to the latter aspect in more detail, to be practical within the amateur photographic market, a "wallet sizing" conversion device must meet somewhat rigid "human engineering" design criteria. For example, the prospective purchaser will not be interested in any form of device which can be construed as one wherein he or she will be called upon to modify a camera in any manner or form. The procedures to be carried out by the purchaser must be simple in the extreme and not involve the camera structure itself nor conventional camera film loading procedures. Next, the "wallet sizing" conversion must operate reliably while remaining simple in structure and operation. Further the conversion must be just as simply reversable to regain the larger format image size. Additionally, an artistically desirable format geometry present as an elongate rectangle should be preserved even in the smaller format. Next, the cost of such arrangement must be commensurate with the corresponding lower cost of popularly priced cameras.